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Damp on chimney wall

Postby rogerc41 » Sat Dec 31, 2011 3:41 pm

Hi all,

I currently have a patch of localised damp on the chimney in my kitchen. The house is 1920's brick semi-detached. The chimney area is open upto about 4 foot from the ground and currently houses the CH boiler. the wall on the right of the boiler, on the face open to the room not the internal chimney face, has a damp patch at the skirting upto around 12 inches up the wall and 2 foot in width. This is an interior wall and there are no other damp issues in the house (I think the previous owners had a damp proofing injected as there are a series of holes around the bottom of the exterior walls).

Just wondering what actions to take to either investigate and resolve it. I didnt really want to cover it up and then have it come back again. would it be best to remove the paint and plaster to see what was happening with the bricks behind, then think about sealing it??

All help and replies much appreciated.
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Postby welsh brickie » Sun Jan 01, 2012 4:55 pm

I think removing the plaster is 1 option,Try painting it with a pva solution first though it may stop it.
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Postby rogerc41 » Mon Jan 02, 2012 3:12 pm

Thanks for that welsh brickie. May do a little investigation work first just to make sure all is ok underneath bfore covering it up.
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Postby Refresh PSC » Sun Apr 22, 2012 6:40 pm

Dampness around chimney breasts is common due to 2 main reasons.
Firstly, most original fireplaces have a stone or concrete hearth which has no damp proofing membrane beneath it allowing ingress from below which can then track onto surrounding masonry and contaminate.
Secondly, a lot of chimneys are not capped, therefore rainwater will seep down and saturate the lower courses of brickwork and affect plaster on the internal faces which is a common mistake made by a lot of damp proofing companies that do not check the chimney stacks first.

My recommendation would be to test for salt deposits on the plaster/brickwork, if salting is apparent, the problem is due rising dampness and if no salting present, chimney caps or an external leak is your best bet.

Sorry Welsh bricky but PVA is not a miracle cure and can cause more problems due to inhibiting the natural evaporation of moisture from the affected area.
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